.\"
.\" Sun Microsystems, Inc. gratefully acknowledges The Open Group for
.\" permission to reproduce portions of its copyrighted documentation.
.\" Original documentation from The Open Group can be obtained online at
.\" http://www.opengroup.org/bookstore/.
.\"
.\" The Institute of Electrical and Electronics Engineers and The Open
.\" Group, have given us permission to reprint portions of their
.\" documentation.
.\"
.\" In the following statement, the phrase ``this text'' refers to portions
.\" of the system documentation.
.\"
.\" Portions of this text are reprinted and reproduced in electronic form
.\" in the SunOS Reference Manual, from IEEE Std 1003.1, 2004 Edition,
.\" Standard for Information Technology -- Portable Operating System
.\" Interface (POSIX), The Open Group Base Specifications Issue 6,
.\" Copyright (C) 2001-2004 by the Institute of Electrical and Electronics
.\" Engineers, Inc and The Open Group.  In the event of any discrepancy
.\" between these versions and the original IEEE and The Open Group
.\" Standard, the original IEEE and The Open Group Standard is the referee
.\" document.  The original Standard can be obtained online at
.\" http://www.opengroup.org/unix/online.html.
.\"
.\" This notice shall appear on any product containing this material.
.\"
.\" The contents of this file are subject to the terms of the
.\" Common Development and Distribution License (the "License").
.\" You may not use this file except in compliance with the License.
.\"
.\" You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
.\" or http://www.opensolaris.org/os/licensing.
.\" See the License for the specific language governing permissions
.\" and limitations under the License.
.\"
.\" When distributing Covered Code, include this CDDL HEADER in each
.\" file and include the License file at usr/src/OPENSOLARIS.LICENSE.
.\" If applicable, add the following below this CDDL HEADER, with the
.\" fields enclosed by brackets "[]" replaced with your own identifying
.\" information: Portions Copyright [yyyy] [name of copyright owner]
.\"
.\"
.\" Copyright 1989 AT&T
.\" Portions Copyright (c) 1992, X/Open Company Limited.  All Rights Reserved.
.\" Copyright (c) 2009, Sun Microsystems, Inc.  All Rights Reserved.
.\"
.TH GETPID 2 "Jan 27, 2009"
.SH NAME
getpid, getpgrp, getppid, getpgid \- get process, process group, and parent
process IDs
.SH SYNOPSIS
.LP
.nf
#include <unistd.h>

\fBpid_t\fR \fBgetpid\fR(\fBvoid\fR);
.fi

.LP
.nf
\fBpid_t\fR \fBgetpgrp\fR(\fBvoid\fR);
.fi

.LP
.nf
\fBpid_t\fR \fBgetppid\fR(\fBvoid\fR);
.fi

.LP
.nf
\fBpid_t\fR \fBgetpgid\fR(\fBpid_t\fR \fIpid\fR);
.fi

.SH DESCRIPTION
.sp
.LP
The \fBgetpid()\fR function returns the process \fBID\fR of the calling
process.
.sp
.LP
The \fBgetpgrp()\fR function returns the process group \fBID\fR of the calling
process.
.sp
.LP
The \fBgetppid()\fR function returns the parent process \fBID\fR of the calling
process.
.sp
.LP
The \fBgetpgid()\fR function returns the process group \fBID\fR of the process
whose process \fBID\fR is equal to \fIpid,\fR or the process group \fBID\fR of
the calling process, if \fIpid\fR is equal to 0.
.SH RETURN VALUES
.sp
.LP
The \fBgetpid()\fR, \fBgetpgrp()\fR, and \fBgetppid()\fR functions are always
successful and no return value is reserved to indicate an error.
.sp
.LP
Upon successful completion, \fBgetpgid()\fR returns the process group ID.
Otherwise, \fBgetpgid()\fR returns \fB(pid_t)\(mi1\fR and sets \fBerrno\fR to
indicate the error.
.SH ERRORS
.sp
.LP
The \fBgetpgid()\fR function will fail if:
.sp
.ne 2
.na
\fB\fBEPERM\fR\fR
.ad
.RS 9n
The process whose process  \fBID\fR is equal to \fIpid\fR is not in the same
session as the calling process, and the implementation does not allow access to
the process group \fBID\fR of that process from the calling process.
.RE

.sp
.ne 2
.na
\fB\fBESRCH\fR\fR
.ad
.RS 9n
There is no process with a process \fBID\fR equal to \fIpid\fR.
.RE

.sp
.LP
The \fBgetpgid()\fR function may fail if:
.sp
.ne 2
.na
\fB\fBEINVAL\fR\fR
.ad
.RS 10n
The value of the \fIpid\fR argument is invalid.
.RE

.SH ATTRIBUTES
.sp
.LP
See \fBattributes\fR(7) for descriptions of the following attributes:
.sp

.sp
.TS
box;
c | c
l | l .
ATTRIBUTE TYPE	ATTRIBUTE VALUE
_
Interface Stability	Committed
_
MT-Level	Async-Signal-Safe
_
Standard	See \fBstandards\fR(7).
.TE

.SH SEE ALSO
.sp
.LP
.BR Intro (2),
.BR exec (2),
.BR fork (2),
.BR getsid (2),
.BR setpgid (2),
.BR setpgrp (2),
.BR setsid (2),
.BR signal (3C),
.BR attributes (7),
.BR standards (7)
